Haymill Valley is a 7.8-hectare (19-acre) Local Nature Reserve in Slough in Berkshire.

It is owned by Slough Borough Council and managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust.

[4] The site features ancient woodland with extensive reed beds and ponds fed by Two Mill Brook (also known as Two Mile Brook), which flows from Burnham Beeches into the Thames.

[5] At the reserve's southernmost end is a site of an ancient watermill.

[6] Haymill Valley Nature Reserve was declared a local nature reserve status in 1994 by Slough Borough Council.